Sulphur mining



malas J. E. SCHRQEDER SULPHUR MINING Filled March 9. 1922 3 Sheets-Sheet 1 I March 1l, 1930. J, E, SCHROEDER v 1,750,136..

SULPHUR MINING Filed Maron 9. 1922 5 Sheets-sheet s A n N' A" l ,C I '-1 wuemtoz LA, JWM

@wf Y Patented Mar. 11, 1930 JAMES E. SCHROEDEIR., Oli* HOUSTON, TEXAS PATENT OFFlrCE SULPH'UR MINING- Application filed March 9, 1922.

rlhis invention relates to the mining of sulphur from underground deposits and it has special reference to processes and apparatus of the well-known Frasch type. 4

In accordance with the Frasch process, water superheated under pressure is forced down from the surface into contact with the sulphur deposits where it serves to fuse or melt the sulphur, which is thereafter suitably elevated to the surface in the liquid state. To ai largeextent, the operating economy of such a process depends upon the efliciency or effectiveness of operation of the heating medium in its fusion action upon the sulphur, and this, in turn, is. dependent upon the geological formation and structure of the sulphur deposits, and the immediately adjacent strata. If the deposits and neighboring strata are porous in character and contain a0 fissures, crevices and other voids, the heating medium necessarily .runs off or .escapes and i much of the heating medium is lost and the heat thereof uselessly dissipatedin regions remote from the sulphur deposits. A similar condition arises in a sulphur mine under operation when a portion of the sulphur has been removed, leaving large voids which must -be uselessly filled with the heating medium as the `work progresses, and in which the heat is dissipated.

Appreciating these ditliculties and the resulting `inethciency and ineifect-iveness iiowing therefrom, it is one of the objects of the present invention to improve the efliciency of sulphur mining of thisA general character by promoting the effectiveness of the heating medium upon the sulphur deposit in such manner as to locally conne the heating medium to' a large extent to the immediate area of the deposits, thereby conserving its Vheat and applying it directly to the sulphur so thatit will be expended effectively and expeditiously in performing its intended function. y

To this end, it is proposed to introduce compressed air or other suitable medium, having relatively poor heat conducting properties, into the region immediately above the sulphur deposit so as -to lill the voids and thus prevent the escape of the heating medium and the wasteful dissipation of its heat. A ofthe deposit and subsequently through the 100 Serial No. 54223.

layer or blanket of a'relatively good heat-l insulating medium under pressure is thus provided above and in proximity to the sulphur deposits. As the -mine is worked and sulphur gradually removed, this blanket of compressed air or the like is progressively lowered by the supply of increased volumes thereof so as to fillvthe voids left by the removal of sulphur. The air or other heat in'- sulating medium is introduced by means of av suitable well or casing through which it is forced, and suitable apparatus is provided to enable the operator to determine the exact depth of the air layer or blanket, with respect to the location of the sulphur deposit being mined. In this way, the operation may be intelligently conducted and effective and etlicient4 operation of the heating medium may be insured. Obviously, the heat-insulating medium may be utilized in certain formations merely for the purpose of filling the voids left by the removal of the sulphur.

ln somecases, it will be found expedient to provide an auxiliary casing or well extending to a region somewhat below the area of the deposit operated upon and to remove therefrom a portion of the water or heating medium that has largely given up its heat and thus cooled olf to a considerable degree, a. circulation of the heating-medium being thus provided. Preferably, water that has dropped in temperature to approximately E200o F.y is thus removed, and so long as it is above that temperature Ait is allowed to re- Y main in the mine. Although below the meltl'mg point of sulphur, water of a temperature of 200 F. has a very benecial effect upon the deposit and contributes to the effectiveness of the heating medium being constantlyintroduced. y

A further object of the invention is to provide a process Yof sulphur mining that shall be especially adapted for operation upon deposits occurring in a moundlike geological formation, where the bulk of the deposit lies in the form of an annulus and which contemplates foperating upon the deposit by means of producing wells initially located at distributed points around the inner periphery so *I agency of wells progressively located at more remote points and at increasing depths whereby substantially the entire sulphur content of the deposit is eventually removed.

These and other objects of the invention and features by meansof which they are accomplished will be understood by those skilled in t e art from thefollowing description of the invention as illustrated in the accompanying drawings, in which Fig. 1 is a more or less diagrammatic scctional view of a typical mound-like eological formation containing a deposit o sulphur, together with certain apparatus constructed and arranged in accordance with the present invention and by which the present process may be practiced,

Fig. 2 is a diagrammatic plan view of the typical geological formation of Fig. l and showing the arrangement and distribution of the sulphur deposit, together with the location of the apparatus necessary for conducting the present process, and

Fig. 3 is a view similar to Fig. 1, showing the apparatus of the present invention as ap` lied to a somewhat different geological ormation.

Referring particularly to Figs. 1 and 2, as illustrative of the apparatus as applied to a typical mound-like formation or occurrence of the sulphur deposit, the formation illus` trated embodies a plurality of strata repre- I .senting a so-called surface7 formation 10,

lime-rock 11, sulphur deposit l2, anhydrite 13 and salt core 14. In the particular example shown, the mound-like geological formation is such that the main bulk of the sulphur deposit occurs on the slope of the anhydrite in the general form of an annulus, as indicated in heavy section lines in Figs. 1

- and 2, although a relatively thin layer of sulphur deposit lies immediately above the substantially attened top thereof, as illustrated in light section lines of said figures. As will be apparent from the drawings a relatively thick stratumof cap or lime rock overlies the thin layer of de osit and covers a very considerable area. is cap or lime rock contains much water and embodies many large voids.

The mining of the sulphur deposit is effected in a somewhat similar manner to that of the Well-known Frasch process, and for Vof the sulphur deposit.

this reason the apparatus and mode of o erationwill only be brieiiy set forth. -T e' removal of the sulphur from the underground deposit is advantageously accom lished byl each may conveniently comprise an outercasing 20.which extends from the surface S to approximately the upper contour of the sulphur deposit 12, and a so-called top water casing 21. disposed within the outer casing 2O and intimately -connected or sealed thereto at a point 22 somewhat above the upper co tour of the sulphur deposit. This top water casing is perforated throughout the length of the sulphur deposit and terminates at substantially the upper anhydrite contour in an extended projection or anchor 23. Within the casings, hereinhefore mentioned, is a socalled bottom water, casing 24 extending from the surface to a point illustrated by joint 25 below which the casing is extended by means of a short perforated strainer 26 to a suitable gasket or collar 27, the collar being preferably located a few feet above ,the upper contour of the anhydrite 13 and within the sulphur deposit. An extension of this bottom water casing 25 is provided in the form of a so-called sulphur strainer 28 projecting somewhat below the collar l27 and disposed within the lower perforated end of the top'water casing 21. Thelower end of this strainer 28 is closed by means of a disc 29. A pipe 30l for the removal ofthe liquid vsulphuris arranged within the other casings and extends through the collar 27 and into the sulphur strainer 28 fora short distance.

`In addition, an air pipe 32 is centrally located within the several casings above mentioned and extends from the surface to a point within the sulphur deposit somewhat above the location of the strainers 26 and 2 already mentioned. 1

It will be understood that the relative dimensions and ,proportions illustrated are by no means accurate, but are merely for the purpose of indicating in a general way the arrangement and construction of the producing well.

In operation, superheated water and -steam are delivered from a boiler or boilers 35 through a pipe 36 to the upper end of the casing 20 and this Water and steam is forced down through the casing and, at the point 22,

into the top Water7 casin 21 from which it emerges through the per orations provided therein. Additional superheated water and steam at a higher pressure is forced into the bottom water casing 24 from theboiler or boilers 35 through a pipe 36 and a suitable force pump 37. This water and steam is forced down the well and'emerges through the perforations in the lower end of the bottom Water casing,- comprising the strainer 26. In this way itis insuredthat the heating medium is delivered into the surrounding sulphur deposit fat a point adjacent the iower end of the well.

This` highly heated water and steam, thus delivered to the sulphur deposit adjacent the lower end of the well, permeates the adjointhe sulphur content of the deposit.

lll

v siderable degree,

- mirarse ing sulphur-bearing material and the heat thereof eventually fuses, melts or liqueiies The molten surphur collects around the bottom of the well and is removed in any suitablel manner. As illustrated in the drawings, a convenient mode of removing or elevating the liquid sulphur to the surface is by means of air pressure through the agency of an air compressor 4l@ which compresses air to a high d-egree and delivers it through a pipe lll to the upper end of the air pipe 32, whereby it is conducted downwardly into the well. rllhe molten sulphur, collecting around' the bottom of the well, dows inwardly through the perforated lower end of the top water casing 2l and. thence through 'the sulphur strainer 28 after which it rises through the pipe 30 and is elevated to the surface in a well-known manner by the 'highly come pressed air emerging from the pipe 32 near the bottom of the well. The sulphur as it reaches the surface is discharged from the upper end of the pipe 30 through a piped?) and is delivered into a suitable vat or other receptacle ad.

lhe structure and operation of the producing well per se, just described, is in accordance with the well-known Frasch process and in itself forms no part of the present invention, except as it enters into combination with certain other features thereof to be hereinafter set forth.,

'lihe essence of the lllrasch process, just described, lies in the fusion or liqueiication of the sulphur content of the deposit by means of the introduction of a heating medium.` llt is manifest that the eciency and commercial feasibility of mining sulphur inthis manner depends upon-the effectiveness and eciency of the heating medium toward its intended purpose. Obviously the heat eiiiciency is to a large degree dependent upon the geological structure of the adjoining strata. lf the overlying stratum or formation be such as to embody voids, fissures, or crevices tov a conmuch of the heat of the heating medlum is permitted to escape and is uselessly dissipated.

The present invention is directed to the conservation of the heating medium to locally confine its operation to the sulphur deposit where substantially all of the heat is usefully employed in a localized area Whereby economy and eiiiciency of operation are secured.

' This is accomplished by preventing the useless dissipation of heat in filling the voids of the over-lying cap or lime rock 11 with a heat-insulating medium, suchr as compressed air. To this end, an vair well A is located at the highest point of the lime-rock stratum containing open voids, which, in the present instance, is assumed to be substantially the mid-point ofthe area-denoted `in Fig.. 2 by the dotted line h, which indicates the boundary of the relatively thin sulphur deposit lying over the flattened top of the anhydride stratum.

ilFhe air well it comprises an outer casing 50 which is sunlr to substantially the upper contour of the cap or lime-roclrll. rllhis casing may, if desired, be extended into or through the cap rock, in which event, it is preferably perforated. t pipe 5l is disposed therein and normally projects through the cap roclr to the upper surface of the relatively thin layer of sulphur deposit l2. 'llhe upper end of the pipe 51 is provided with a controllable valve 52, while the upper end of the vcasing 50 counicates by means of a pipe 53 with an air compressor 5d of suitable construction. 'lhe pipe 5l is termed a theft pipe and is adapted to be adjusted in position, as desined, in order to dehnitely determine the depth of the air layer with respect to the location of the sulphur bed being operated upon. Normally theq lower end of the theft pipe-5l lies in the plane of the upper contour of the sulphur deposit ll.

ln order to fill the voids of the cap or limerock il., lying immediately abovethe stratum "of sulphur-bearing material, air at a high degree of compression is forced down through the casing 50 and into the voids of the cap rock, thereby completely filling-the voids and thus preventing the entrance therein of the' heating medium. lin this way the useless dissipation of the heating medium, which is necessarily incident to processes of this character that have been employed in the past, is substantially obviated. The compressed air, thus introduced, forms an extended horizontal layer or blanket immediately, above the sulphur-bearing deposit, as is shown in horizontal section lines in Figs. l and 2. inasmuch as air is a very good heat-insulating medium, this air layer serves ed'ectively to locally conne the heat of theI heating medium to the region of operation upon the sulphur deposit,

The degree of compression of the air, thus introduced to form the heat insulating layer,

depends upon the particular conditions and by the location of the lower end of the theft f lpipe 51 and should be such that all the voids o'f the cap rock are filled. Ifwater emerges from the'upper end of the theft pipe 51, itis Y an indication that additional amounts'of air must be introduced in order to lower the air 4layer to a point corresponding to the lower end of the theft pipe. The depth of the air layer may be ascertained by adjusting the `height of the theft ipe until air begins to on so as to insure the filling of all of the voids.

By reason of the high temperature existing in the water in the neighborhood of the air layer, this blanket of air can be' maintained at relatively small cost inasmuch as the air is practically insoluble under these conditions of heat.

The utilization of the heat-insulating layer of air, as just described, is especially advantageous when operating u on sulphur beds occurring in a stratum of tlie general formation lindicated in Figs. 1 and 2, where thebulk of the sulphur deposit lies in the form of an annulus and a very large area of cap rock filled with voids occurs above and within the annulus. With such a geological formation, it is evident that the aggregate f the voids of the overlying cap rock is enormous and, therefore, an immense amount of heat would be uselessly dissipated therein, were no suitable provision made for confining it to the operating area.

As the operation is carried on and the sulphur content of the deposit gradually melted and removed, the area of volds is greatly increased. Therefore, as the sulphur is removed and the production graduall lowered, the layer of heat-insulatin 4me ium is also progressively, lowered to fil the voids left by the removal of the sulphur. In a formation, such as illustrated in the drawings, thefair layer may be advantageously lowered at least until it reaches the upper contour of the anhydrite, thereby closing off all of the area above it from the dissipation of heat and confining the heat medium to localities Where it will be effective upon sulphur deposits.

Obviously, the utilization of the air layer is not restricted to geological formations embodying cap rock filled with voids, but may be advantafgeously employed under other conditions or the purpose of merely filling the voids left by the removal of the sulphur content.-

In carryin on the present process upon a mound-like ormation such as illustrated, it is particularly desirable and expedient to begin-the removal of'sulphur by means of wells located around vthe inner periphery of the annular deposit, where they lare so disposed as to initially remove the sulphur occurring at the highest ints of the deposit.

In thls way, any -mo ten sulphur that is.

liquefied and not removed flows to lower moved to levels and will subsequently be'jreached and elevated to the surface as lproduction is later carried on by other wells sunk to greater depths.

As the production from the,first producing wells P is reduced to such an extent as to indicate that the sulphur content above and adjacent thereto has been substantially removed, these wells are closed off and new wells vP are drilled and operated. These new wells are located somewhat further away from the air well A and extend down into the sulphur de osit to lower depths. The producing wel s are thus progressively moved outwardly from the center of producdepths.

This mode of conducting the production is of especial importance in that it insures that substantially the entire sulphur content is eventually removed.

The present process -also contemplates the provision of a plurality of so-called bleed wells B which are located beyond the producing wells and at even greater depths. These bleed wells are for the purpose of insuring a circulation of the heating medium and removin a portion of the water introduced throng the producin Wells which, upon giving u its heat in i s fusion action upon the sulp ur, finds lits way down to lower levels. These wells comprise a casing 60 extending from the surface to the desired depth below the lower ends of the producing wells. The upper end of the casing is rovided with the regulatable valve 61 and ischarge pipe 62 to carr off the water emerging therefrom. A suitab e` thermometer or other temperature-indicating device 63 is provided at the upper end of the casing to determine the tem erature of the outllowing water. In con ucting the rocess, the valve is kept open to permit the discharge of cool water until the thermometer 63 indicates a temperature in the neighborhood of 200 F., at which time the valve 61 is closed. In this way a portion of the water which is partially cooled, is periodically or, if desired, continuously reermit the supply of additional amounts of eatin medium, thereby creating a more or less de 'te circulation instead of allowin the heating medium to become stagnant. he water in the sulphur-bearing material is thus maintained above a temperature of 200 F., and although this temperature is below the melting point of sulphur, it has a beneficial effect upon the sulphur content and increases the efficiency of the heating medium. p

Referring to Fig. 3, the geolo 'cal formation therein shown differs slightyx' from that of Figs. 1 and 2, in, that the contour of the various strata is more nearly horizontal,-

- that is, the strata lie in more or less horizontal layers. The apparatus and .Inode of option and at tlm 'same time sunkv vto greater y eration employed in connection with such formations is similar to that already described and diiers only in that, by reason ofl the horizontal disposition of the formation, the producing Wells extend down through the layer of compressed air or other heat-insulating medium.v The process, so :Ear as its operation is concerned, is similar to that already described although it is necessary to make suitable provision for preventing the escape of the air cushion While drilling through the stratum in which the air layer exists.

During this drilling operation, it is desirable to thoroughly seal the opening between the Well casingand the drill stem by continually introducing therein from the surface a medium ladened with mud or other suitable maf terial. Any convenient means of introducing this mud-ladened fluid may he employed.

VOf course, as Soon as the Well is drilled through. th'e stratum in which the air layer exists and the casing subsequently lowered therethrough, there is no further necessity of introducing more mud-ladened Huid to seal the Well against the escape of the air, p

inasmuch as thecasing itself completely performs this function. i

Although the invention as embodying more or less specific details of construction, arrangement and location of parts and mode of operation, it Will be under- Vaus stood that the invention is notl so restricted and that many modications may be made therein Without departing from the spirit and scope of the invention, thereiore,` only such limitations should be imposed as are indicated in the appended claim.

Iclaim: l r

Apparatus for mining sulphur from underground deposits having, in combination, a producing well for introducing a heating medium into the deposit to effect the melting of the sulphur content and for removing the sulphur so melted, an air Well extending down to the highest point of the lsulphur-deposit lor conducting air to form a heat-insulating layer immediately above the deposit,

means connected to said air Well for highlyv compressing the air and forcing it down the Well and a theft pipe disposed Within said air Well for determining the depth of the l Vair layer above the deposit.

In Witness whereof I have hereunto set my hand. and seal this 15th day of February,

JAMES E. SCHROEDER.

has been set forth Y 

